Table 1 List showing location, glass type and refractive index of the tephra layers
Tephra name | Locality | Latitude, longitude | Shape of glass shards* | Dominated heavy mineral | Refractive index of volcanic glass (n) |
|---|---|---|---|---|---|
Ahn (AhG) | Juniso, Kamakura City | 35°20′01.2"N 139°34′49.0"E | bw, str | bi > opx | 1.498–1.500 |
Onr | Onaura, Katsuura City | 35°08′27.4"N 140°17′24.5"E | bw, str | bi > opx, ho | 1.497–1.499 |
IkT19 (Ikg1) | Ikego, Zushi City | 35°18′37.4"N 139°36′30.3"E | bw > str, sb, fib, spg | - | 1.500–1.506 |
An158.5 | Nagasaki, Futtsu City | 35°13′20.9"N 139°54′34.5"E | bw > str, sb, fib, spg | - | 1.500–1.507 |
IkT16 | Ikego, Zushi City | 35°18′34.8″ N 139°36′35.6″ E | sb, spg, str > bw | - | 1.507–1.511 |
An157.5 | Nagasaki, Futtsu City | 35°13′19.6"N 139°54′39.0"E | sb, spg, fib, str > bw | - | 1.508–1.510, 1.513 |
Ng | Hisagi, Zushi City | 35°18′27.2"N 139°34′07.0"E | bw, str, sb, spg, fib | opx > ho > > cpx, bi | 1.498, 1.502–1.505 |
Ky25 | Okugome, Kimitsu City | 35°10′41.9"N 140°02′09.3"E | bw, str, sb, spg, fib | opx > ho, cpx > > bi | 1.503–1.505 |